Where did the moons of Mars come from? That’s a question scientists still can’t answer. We know that Earth’s moon most likely formed in a giant collision with Earth about 4.5 billion years ago. Some moons in the solar system, such as some of Jupiter’s smaller moons, appear to be captured asteroids. Which of these two formation pathways applies to Mars’ moons Phobos and Deimos remains unknown, but we may soon know the answer. A Japanese spacecraft to be launched next year will try to bring back samples from Phobos. The mission builds on exciting new results from the United Arab Emirates (UAE) orbiter on Mars, suggesting a planetary origin for the two moons. “There’s room for wonder, but I think we’ll figure it out,” said Jemma Davidson, her girlfriend at Arizona State University.
On April 24, the UAE announced that its orbiter Hope had surveyed Deimos, the smaller of Mars’ two moons. The spacecraft returned some of Deimos’ best data and images from as low as 100 kilometers above the lunar surface. These results confirm that the composition of Deimos is that of an asteroid previously flagged as likely to be the source of Deimos and Phobos, D-type asteroids in the outer asteroid belt between Mars and Jupiter. It suggests that it is more closely aligned with Mars than its class. “We don’t believe that [Deimos] said Hesa Al Matrusi, the mission’s chief science officer at the Mohammed bin Rashid Space Center in Dubai.
To find out, scientists want to bring Phobos samples back to Earth. A Russian attempt failed in 2012 when the Phobos-Grunt spacecraft crashed into the Pacific shortly after launch. I never got out of it,” he said. The Japan Aerospace Exploration Agency (JAXA) wants to avoid the same fate with its Mars Moon Exploration (MMX) mission. The solar-powered spacecraft, scheduled to launch in September 2024, weighs more than her three tons and is about the same size as her SUV. It aims to head to Phobos in 2026 to scoop up samples and bring them back to Earth by 2029, before entering Mars orbit in August 2025. The mission is “very complicated” but should be very rewarding, says Patrick Michel of the Côte d’Azur. French Observatory, European Collaborator at MMX, Member of the Mission’s Scientific Committee.
On April 17, NASA and JAXA announced a partnership on the mission. As part of the partnership, NASA will select 10 of her US scientists to work on her MMX and will also provide two of her instruments for the spacecraft. “JAXA has great partners and they are leading this ambitious mission to bring back the first sample of the Martian moon Phobos,” said his NASA administrator, Bill Nelson, in a video of him. said in a message. Post to Twitter“Together, we will deepen our knowledge of the solar system.”
Of the two moons of Mars, Phobos is slightly larger. Both are irregularly shaped like potatoes. Phobos is about 27 km on its longest side and Deimos is 15 km. Phobos is also closer to Mars. It orbits just 6,000 kilometers above the ground and makes one lap every 7 hours and 39 minutes. At an altitude of over 23,000 km, Deimos takes just over 30 hours to orbit. Both moons have been previously imaged by several spacecraft, most notably his 1977 NASA Viking 2 Orbiter, the 2000s Mars Reconnaissance Orbiter, and even his 2013 Mars It’s a Curiosity rover that has moved from the surface. Month.
Japan’s MMX mission tries to change that. It builds on the success of the national asteroid sampling missions Hayabusa and Hayabusa 2, which returned asteroid samples in 2010 and 2020, respectively. However, both took only a few seconds to brush the surface of the target. MMX lands at two of his locations on Phobos, and on the surface he collects a total of about 10 grams of matter over the course of two hours. “That’s the big difference from Hayabusa,” Michel says. The moon’s gravity is only 1,000th that of Earth’s, and because of its unusual shape, surface manipulation of Phobos presents many challenges because of its uneven gravitational field. MMX he collects samples using two methods. With an extendable arm coring sampler he collects specimens from depths greater than 2 cm and with a pneumatic sampler he lifts the material off the surface.
However, MMX strives to ensure that smaller landings are made before collecting samples. In 2026 or 2027, the spacecraft will deploy a small rover developed by French and German scientists to the surface. A rover the size of a microwave oven will be dropped from a height of 45 meters as the spacecraft practices landings. After rolling on the surface, the rover is undone by her four extendable wheels and the 100-day mission begins. The moon’s weak, erratic gravitational pull means the rover cannot move faster than a snail’s pace, despite weighing just 25 kilograms.
“Going faster than 80 millimeters per second could tip the rover or even leave the Phobos system,” says Markus Grebenstein, the rover’s project manager at the German Aerospace Center. Given the rover’s limited lifespan, its speed limit “basically limits its range to about 100 meters.” Still, the rover should be irreplaceable. It will study the surface of Phobos, giving the primary MMX spacecraft important information about the lunar surface properties and incorporating it into two landing attempts. The rover will also test robotic manipulation on small objects like Phobos. A stretch goal might be to push the rover to its limits by trying to flip the rover over by spinning the rear wheels at the end of the mission. “The rover can easily backflip,” he says Grebenstein. “When life comes to an end, we may be allowed to conduct such experiments.”
MMX’s goal is to sample “the most pristine material on Phobos,” says Michelle, which may contain hints to its origins. Samples may also have hidden bonuses. The surface of Phobos is thought to be covered by some material ejected from Mars by an impact and settled on the Moon. So when Japan brings his 2029 sample to Earth, it will likely contain the first pristine samples collected from Earth itself, making it one of NASA’s multi-billion dollar Mars sample returns. It is not expected to defeat the effort and send samples back to Earth until 2033. at the earliest by a considerable margin. MMX samples are unlikely to contain evidence of past life or habitability on Mars, but may provide useful information about past geology. “I hope we can capture them with a sampling mechanism,” says Michelle. “On this mission, we were able to have the first recovered sample from Mars.”
After two landings, MMX will leave the surface and capsule the collected samples back to Earth. The main rover itself will remain in Mars orbit and then perform a Deimos flyby to study that moon from a distance, while the sample His capsule will land in the Australian desert in July 2029. Davidson said he was one of NASA’s chosen scientists to then conduct a survey. The sample returned to Earth. “By looking at the mineral, you can tell if it’s a mineral from Mars or a captured asteroid,” she says.
If the samples turn out to be captured asteroids, this discovery could have interesting implications for how they migrated from the outer asteroid belt to Mars. , which in itself poses a problem if it was formed by a collision earlier in Mars’ history. In particular, it raises the question of how small objects like these formed around planets, suggesting an immeasurable size of about 3,500 km across compared to the size around our own Moon. big earth. “This doesn’t fit the model we have of what material from a giant impact might look like,” says Davidson. “Whatever we figure out, we need to rethink what we assumed we knew about these processes.”
MMX and Hope represent renewed interest in the Martian Moon and were proposed by the Planetary Society in 2015 as prime locations to begin human exploration of Mars. Logsdon, co-author of the Planetary Society report, said, “Even if we couldn’t send humans to the surface of Mars, we could have sent them to a rendezvous with Phobos and Deimos.” increase. It could help us understand how our solar system and its myriad of planets, moons and asteroids formed today. “Understanding how moons formed is critical to understanding the dynamics of the solar system,” he says.
